This invention relates to solid, infusible, iodine-containing polymers usable as X-ray contrast agents for obtaining X-ray photographs of the alimentary tract, and as solid reinforced plastics for the manufacture of radiopaque, flame retardant articles.
Medical X-ray photographs of the alimentary tract are usually obtained by using barium sulfate as the contrast agent. See U.S. Pat. No. 3,017,329. Barium sulfate is a very dense, slightly soluble, inorganic salt which tends to agglomerate and settle out in the stomach. While various suspending agents are used to minimize this problem, none are entirely satisfactory. Barium sulfate has also been reported to cause constipation if not promptly removed from the system, and occassionally, enough is absorbed to produce toxic reactions. U.S. Pat. Nos. 3,891,605; 3,700,957; and 3,507,933 disclose the use of brominated compounds as flame retardant, reinforced plastics, but not as radiopaque agents.
Iodine containing compounds have also been employed as X-ray contrast agents. These compounds, however, are usually absorbed into the body, and then metabolized. The water-soluble iodine containing compounds are usually sufficiently osmotically active at the doses required for visualization, but movement through the tract is rapid and often leads to catharsis.
The iodine containing X-ray contrast agents known in the art have generally employed iodobenzoates with a vinyl resin (U.S. Pat. No. 3,645,955); polyurethane resins (U.S. Pat. Nos. 4,282,876 and 4,250,072); and an alkoxyalkyl ester which is not claimed as a polyester (U.S. Pat. No. 3,361,700). U.S. Pat. No. 3,852,341 discloses the use of triiodobenzoic acid polymers as edible radiopaque agents. However, none of these polymers have been claimed as radiopaque, flame retardants. Japanese Pat. No. 71222579-R discloses the use of trimethyliodide polyethylene/propylene polymers as flame retardant reinforced plastics, but not as radiopaque agents.
It is thus an object of this invention to provide a crosslinked unsaturated iodinated polyester resin that, when ground, produces an excellent X-ray contrast agent. It is a further object of this invention to provide an X-ray contrast agent that does not tend to settle out in the stomach or intestines, but clings to the fine ridges and grooves in the stomach and intestinal lining to give good detailed pictures. It is also an object of this invention to provide a polymer that is water-insoluble and osmotically inactive, and not absorbed into the body. It is a further object of this invention to provide a polymer usable as a solid reinforced plastic for the manufacture of radiopaque, flame retardant, articles.